1. Field of the Invention
The present invention relates to a protective cover for bolt heads and nuts, and more particularly, to a decorative bolt cap for use in automotive, motorcycle and marine applications.
2. Background Art
Many articles of manufacture, and particularly automobiles, employ threaded bolts and nuts to secure various components. For example, automobile engines use numerous bolts to hold the engine together and also to attach ancillary pieces of equipment, brackets, etc. Many such bolts are exposed to the elements and to view.
It is frequently desirable to protect the exposed heads of bolts or exposed nuts so as to prevent corrosion and accumulation of grease and dirt. Furthermore, and even more important to many owners of automobiles, it is often desirable to provide a decorative cover or cap for exposed bolt heads and nuts.
One approach that has been taken to protect and cover exposed bolt heads in a cosmetically pleasing manner is to have such bolts chrome plated. To accomplish this, new plated bolts must be purchased or existing bolts must be removed, polished, plated and then reinstalled. In either case, the process is time-consuming and expensive. Although chrome plated bolts have a cosmetically pleasing appearance, the chrome plate is prone to damage when a wrench is applied. Once the plating has been damaged, the bolt is again subject to corrosion and the cosmetic appearance is lost.
Another approach that has been taken to provide improved bolt head appearance and protection is to employ a cup shaped washer that fits under the bolt head and extends around the exposed circumference of the bolt head. When using such cup washers, it is necessary to replace the existing bolts with allen head bolts to accomodate the "cup washer" design. This method is also time consuming and expensive in that the existing bolts must be removed and replaced with allen head bolts and the cup washers must then be installed. Furthermore, the cup washer alone does not conceal or provide protection for the exposed surface of the bolt head. A separate button shaped cap is required. The cap has a protruding post on the underside thereof with a circumferential groove in which a small O-ring is located. The post is inserted into the hex-shaped recess of the allen head bolt and is held in place by compression of the O-ring. Those caps, it has been found, may jar loose from vibration.
Yet another approach to providing a protective and decorative cover for a bolt head is use of a single cap with an internal O-ring. Such cap includes an internal cylindrical wall having a milled groove that retains an O-ring. The O-ring grasps the corners of a hex-headed bolt or the knurled surface of an allen head bolt. Installation of such caps typically requires lubrication with a small amount of oil. This allows the cap to go on smoothly, but also makes it more likely to fall off when subjected to vibration. Also, because these caps must have a groove milled in the interior surface to retain the O-ring, they have a relatively thick wall that precludes their application in many areas having close clearances. Furthermore, the machining of the groove and the O-ring results in additional expense and operations of manufacture.
As described below, the present invention provides a simple and inexpensive bolt cover that may be used on conventional hex-headed bolts such as those that come as stock fasteners in automobile engines. The cap is securely retained on the bolt head and provides protection from the elements and a decorative appearance.